Control system



March 2, 1943. W.. A. RAY

v CONTROL -sYsTEM Filed March 28, 1941 MLU/JMA @4);

/HL/f/v T02.

Arma/viv Patented Mar.`2, 1943 AUNITED STATES PATENT OFFICE coN'raoL-srs'rEM William A. Ray, Glendale, Calif. Appucauon Mann aaien, serialNo. 'assale (Cl. 23e-'21) 3 Claims.

for rendering the system safely inoperative upon the failure of means'normally controlling the value of the condition. I

Another object is the provision, in ar iluid control system, of a safetyvalve 'connected in series with an automatically operated valve normallycontrolling `the flow of uid, the safety valve being maintained in openposition only while the value of a condition resulting from the flow offluid remains within normal limits.

Another object is the provision, in a heating system employing :duidfuel, of means of the character described in the preceding objzectwhereby fu'el ilow is obstructed upon abnormal rise of temperature;additional means being provided whereby upon extinction of the pilotburner flame the fuel ow is also obstructed.

Another object is the provision of a combination control device, whichcomprises a condition responsive device with which is associatedindependent control means actuated in response to abnormal change in thesame condition.

Other objects andadvantagesgof my invention will be found in thedescription, the drawing,

A and the appended claims.

For complete understanding of the invention.

reference may be had to the following detailed.

description and accompanying drawing wherein:

Figure 1 is a mainly diagrammatic view of heating control apparatusembodying my present invention; and

Figure 2 is a transverse section taken generally along the line 2-2 ofFig. 1.

In the drawing, the numeral Il indicates a main burner which isconnected by a conduit I2 to the outlet I3 of a fluid pressure operatedvalve generally indicated at I4. Connected in series with and ahead ofvalve I4 is another valve I5 of the rotary plug type, tol the inlet ofwhich is connected an electromagnetically controlled safe'- ty valvegenerally indicated at I6.

The valve I4 comprises a casing I1 having an opening in its top wallwhich is'closed by a iiexible diaphragm I8. Securing the diaphragm tothe casing and providing a pressure chamber thereabove is a housing I9.Extending from a pressure plate 20, secured to the underside of thediaphragm, is a stem 2| which is pivoted at its lower end on anintermediate portion of an arm 22. This arm is pivotally mounted ateneof its ends on a pin 23 secured to the casing. Pivotally connected toanother intermediate portion of arm 22 is a stern 24 for a closuremember 25. which closure member is cooperable with a valve seat 26provided in the bottom wall ofthe casing.

A compression spring 2l, connected to the other end of arm 22 and to aside wall of the casing,

is so arranged as to eifect snap-action of the closure member in itsopening and closing movements 'as arm 22 moves past center. So that thissnap-action may be fully effective, the upper and lower portions of stem2I are interconnected by a lost-motion device 40. Urging the diaphragmand the closure member upward, is a compression spring 23.

The safety valve I6 comprises acasing 2,9 having a ported partition 30providing a valve seat 3l. Cooperable with this seat is a closure member32 mounted on a rod 33, the free end of which sealingly extends througha side wall of the casing and is provided at its outer end with acompression spring 34 which urges the closure member 32 toward its seat.Mounted in the safety valve casing 29 is an electromagnet 35 comprisinga U-shaped core 38 which carries on one of its arms an energizing coil31.

Mounted on the stem 38 of the plug valve is a cam 39 which, in therotation of the plug valve, is adapted to engage the outer end of rod 33and thereby move the closure member 32 away from its seat and intoengagement with the pole faces of the electromagnet core 36. Theclosure'member 32 is constructed wholly or in part of magnetic materialso that when it is brought into engagement with the core, while the sameis energized by passage of current through coil 3l, the closure memberwill be magnetically retained in open position against the bias ofspring 34.

The electromagnet 35 is so designed that the closure member 32 ismagnetically held only when it is rst brought into engagement with thecore, no attraction of the closure member through space beingcontemplated. ItI Will be noted that the cam 39 is so arranged withrespect to the plug valve that the same is closed when the safety Valveclosure member is `moved thereby to its open position. The generalcombination of plug valve and safety valve shown herein is described andclaimed in my copending application Serial No. 319,735 filed February19, 1940.

Mounted in a wall 45 of a boiler 48, which is heated by the main burnerII, is a combination thermostatic control device generally indicated 2.v at 1L-and cemprsiag a thermal buib'n which is sealingly mounted in theboiler by means of a 1 boiler wall.

fitting 4 9, threaded in aflange .50 welded to the outer end of theiltting'and surrounding the bulb,

" Vis provided for the compression of packing material 52 which servesto sealingly hold the bulb in position.` The outer end of the thermalbulb is iluidlyconnected by a pipe 53 to the valve housins 1,9, A

'I'he thermal bulb is of conventional type and contains a-volatile-fluid which, upon a predetermined rise of temperature of the boilerwater,

expands and thus ,produces a pressure Within housing `I9 aboveA thediaphragm which is effective to move the same downward against the biasof spring 28 so that closure member 25 is brought into engagement withits seat.

. Mounted on an outer portion of fitting 43 and in good thermalconnection therewith is a curved bimetallic strip 54, lto the free endvof which is insulatingly secured a metal strip 55 which carries anadjustable contact screw 55 cooperable with a relativelyfixed contactelement 5l insulatingly mounted on another portion of the fitting 49'and 'normallyinengagement therewith. Surrounding-the bimetallic memberis a cap 53, secured -to the 4fltting`49 and insulatinglySupportingterminals 59. to which the contact elementsv 56 and 5l are`connected by wires 50 and 6 l respectively.

For the energization of the electromagnet 35,

position' by the bimetallic member at normal operating temperaturesofthe "boiler, With the parts in the ppsitionsshown in thc drawing,.fuelsup'ply to both the main burner I I and the pilot burner 6451sobstructed by the safety a valve closure vmember 32. I tion ofthesystem, the plug valve I5 is rotated Y from its open position, as shown,to a closed poi' sition wherein engagement of cam 38 with the end of rod33 moves closure member 32 away from its seat and into engagement withthe pole To initiate opera-'- faces of core 35', whereupon fuel can flowthrough a pipe 58, connected to the outlet of the safety valve, tothepilotburner 64 where it is lighted. The plug valve is manually retainedin safety-valvelopening position until the thermoelectric device ,52`hasbecome sufficiently heated vby the pilot burnerflame togeneratecurrent in an amountfsufllcientA to cause the electromagnet to hold thevvarmature-closure member 32 in the position shown by the broken-lines.When this occurs, the plug valve-may be returned to its open position,fuel then' flowing to the automatic valve I4 which, if Vthe water in theboiler is cold, wil1 be in open' position on account of the-con-Itraction f the fluid in the thermalbulb 43. i Fuel can therefore nowflow to the main burner Il where it i's'ignited bythe pilot burner name.When the temperature of the boiler water reaches` a predetermineddegree, the pressure of the 'fluid in thelthermal bulb, applied tothe-dia phragm Il, effects closure of the automatic valve.

A hollow nut l, threaded in the" deenergizing electromagnet 35. The

Upon resultant cooling of' the water, due to reduced fluid ,pressureabove the diaphragm the valve yreopens runder the force of spring 28;'recycling of the automatic valve maintaining thel watertemperaturebetween predeterminedlimits.

If, due to faulty operation. of the automatic valve or its controlmeans, or from other causes, the temperature of the water rises to anabnormal degree, the bimetallic arm 54 warps outwardly, opening contacts55 and 51 and thereby safety valve closure member 32 is thus permlttedtoreturn to its seat under the force of spring 34.

Fuel flow to both the main and the pilot burner f is thereforeobstructed' and the system must be manually reset" as described above toreinitiate operation after the cause of the failure has been corrected.lAs has beenpointedvout, the bimetallic member is in intimate thermal`contact with thetting 43 (which fitting is preferably .of metal havinghigh heat conductivity, such as brass) and is .insulated-from thesurrounding atmosphere by the cap 53. The bimetallic member is thereforeapproximately at the temperature of the boiler water. angulararrangement of contact .51, a wiping action occurs in the relativemovement of the contacts.`

An additional safety feature is provided b y the pilot-burner-heatedthermoelectric device. If the pilot burner should be accidentallyextinguished, upon cooling of the thermoelectric device the resultantcessation of current generation deenergizes the electromagnet and thesafety valve closes.

While I have herein shown anddescribed my inventi'on in connection witha water heating system,`it is obviously also adapted to the control-ofother 'condition changing systems, such as room heating, refrigeration,fluid pressure andV the'like, wherein additional safety means aredesirable which becomes eil'ective upon the failure of the automaticcontrol means, means responsive to the various conditions beingsubstituted for the thermostats shown. I therefore wish it to beunderstood that the system herein shown and described. isv merely by wayof illustrationand that I intend therefore to be limited only lbythescope'v of the appended claims. The term space as vemployed intheclaimsis intended to de'ne any condition of 4 4 first valve forsupplying fluid fuel to said burner,

`thermostatic means responsive to the temperature voiY said medium forcontrolling said ilrst valve so that the temperature of the medium isnormally maintained `between predetermined limits, said thermostaticmeans including a thermal bulb immersed in said medium, a safety valveconnected-1 in series with said first valve and biased to closed iposition,l manually operable means for opening said safety valve. .meansfor normally retaining said lsafety valve in open position against theforce of said bias, and thermolstatic meansmounted on saidl thermal bulbfor Y .rendering saidV safety valve retaining means ineffective uponabnormal rise of temperature a d-. jacent-the bulb.

2. In a heating control system for a space.: a

ture yoi? said medium for controlling said iirst valve so thatthetemperature of the medium is normally maintained between predeterminedlimits,said thermostatic means includinga thermal bulb immersed in saidmedium, a -safety valve connected in series with said rst valve andbiased to closed position, manually operable means 1 for opening saidsaiety valve, electromagnetic VV means eiective whenenergized to retainsaid safety .valverin open position against the force of said bias whenit ls irst brought to that posito said burner, thermostaticmeansresponsivev to v the temperature of said medlum;i'or automatifcally operating'said valve so that the temperature of the medium isnormally maintained-between "predetermined limits, said thermostati'cmeans including a thermal bulb cimmersed in s'aid mediuxn, a safetyvalve connected in series with said pressure'operated valve and biasedto closed po-' sition, manually operable means for opening said lsafetyflvalve, electromagnetic means leiective `when energized toretainsald safety -valve"l in tion by said manual'- meanaandlthermostatic said safety .valve is closed burner is obstructed. i b

3. In 'a heating control system' for a space: a ,burner for heating themedium'in said space, a

'open position against the force of said bias when it' is rst brought tothatl position bylf'said fmanual means; and 'thermostatic switching;means mounted on said thermal bulb, .said switching means beingeffective upon abnormal rise oi'tem-V perature adjacent said bulb todeenergize said electromagnetic means so that said safety valveis-closed and fuel supply'to the burner isobv 20 structed. pressureoperated valve for supplying fluid fuel WILLIAM A. RAY.

